Generally, in comparison with a local area network (LAN) or a wide area network (WAN), a personal area network (PAN) allows each person to have his own network. For example, the PAN may be applied to various fields such as a wireless sensor network, a home network, etc. In order to embody the PAN through a wireless method, a low-power wireless personal area network (LoWPAN) has been standardized in accordance with IEEE 802.15.4-2003, in addition to a high-speed wireless personal area network (WPAN) in accordance with IEEE 802.15.3.
An interface identifier of a LoWPAN device is based on EUI-64 (or EUI64). The interface identifier may be used for making a routing table for multi-hop routing in the LoWPAN.
Considering the limited functions of the LoWPAN device, such as low power, limited memory space, small packet size, etc., usage of the on-demand multi-hop routing may be limited. Additionally, when many devices are applied to the LoWPAN, using the routing table becomes difficult. That is, the on-demand multi-hop routing method may set an effective path in an ad-hoc network or a mesh-type wireless network, but the on-demand multi-hop routing method requires each node to employ a routing table. However, the LoWPAN device has limited memory space in general, so that it is difficult to build a routing table.
In order to solve the above-mentioned problem, a hierarchical routing method has been developed. However, according to a conventional hierarchical routing method, new nodes are concentrated to a specific position. Therefore, when the new nodes require network participation, address spaces for allocating the new nodes are limited. Therefore, a portion of the new nodes may not participate in the network even though used address spaces do not exceed the total amount of the network.
Furthermore, when a mobile node moves to another position with an address received from a specific node, it may not be possible to transfer a packet to the mobile node through the hierarchical routing. Additionally, it may not be possible to distinguish a temporary node, which temporarily participates in the network, from nodes, which have been already built, to induce problems for building routing paths and other control problems.